The present invention relates to a control system for an unmanned, mobile robot which has drive wheels to be capable of automatically travelling along a predetermined path.
A mobile robot designed for unmanned movement is sometimes used for cleaning the floors of buildings. Such a robot may be equipped with a vacuum cleaner and/or sweepers to clean a range of a floor which it travels. Prior art system proposed for controlling the travel of the mobile robot includes one which lays guide cables along a predetermined path of travel of the robot so as to generate an electromagnetic wave. The robot will be guided by the cables while sensing the magnetic field by means of a sensor. Another prior art control system uses optical marks or tapes which are located along the path of travel so that the robot may follow the path sensing the marks or tapes.
The prior art control systems described so far commonly achieve unmanned robot movement along a predetermined pattern by means of guide means in one form or another. A problem encountered with such guide means type systems is that troublesome work is required for setting and changing a running pattern. Another problem is that the installation of such guide means on floors is undesirable for some kind of buildings. Additionally, where an obstruction is positioned in a predetermined path, the robot cannot travel any further unless it is removed.
Also known in the art is a control system which loads an operation control circuitry of a mobile robot with a program, so that the robot may be automatically steered based on the program. This suffers from the drawback that the program has to be changed every time the dimensions and configuration of the floor to be swept are changed. Generally, various equipments and fixtures are arranged in a room of a building which constitute obstructions to the travel of the robot. Therefore, the program has to be designed in due consideration of such obstructions resulting in prohibitive amounts of time and labor required therefor.
Furthermore, all the prior art control systems described above share a disadvantage that they lack a function which allows a robot to judge the surrounding conditions and, therefore, the robot cannot take an adequate measure against a change occurring therein.